Exposure method and apparatus

ABSTRACT

An exposure apparatus transfers a pattern of a mask onto a substrate and includes a covering member which is disposed in the exposure apparatus and which substantially isolates a predetermined spacing from outside gas. The covering member includes a first thin film made of a first material which blocks penetration of the outside gas with respect to the predetermined spacing and a second thin film having a low degasification property and made of a second material of at least one of a metal and an inorganic substance. An exposure method transfers a pattern of a mask onto a substrate and includes the steps of isolating a part spacing of an optical path spacing for an exposure beam which transfers the pattern of the mask onto the substrate from outside gas by using such a covering member.

This application is the national phase under 35 U.S.C. §371 of prior PCTInternational Application No. PCT/JP00/03389 which has an Internationalfiling date of May 26, 2000 which designated the United States ofAmerica, the entire contents of which are hereby incorporated byreference.

DESCRIPTION

1. Technical Field

The present invention relates to an exposure apparatus which is used totransfer a mask pattern onto a substrate in a lithography method formanufacturing a device such as a semiconductor device, an image pickupdevice (such as a CCD), a liquid-crystal display device, a plasmadisplay device, or a thin-film magnetic head. More particularly, thepresent invention is preferably used in using an exposure beam in avacuum ultraviolet (VUV) radiation region having a wavelength of 200 nmor shorter.

2. Background Art

Generally a conventional exposure apparatus such as a stepper used tomanufacture, for example, a semiconductor device, has a construction inwhich a wafer stage section, a reticle stage section, a projectionoptical system, an illumination optical system are mechanicallyintegrated with each other. The integrated construction is supported ona floor via a vibration-isolating construction. In addition, a measuringsystem for measuring the position of a movable section of each stage ona basis of the projection optical system is attached to a portion of theintegrated construction.

In the exposure apparatus of the above type, a very high resolving powerneeds to be increased to meet an improvement in integration density andfineness degree. The resolving power is proportionate to the wavelengthof exposure light. For this reason, the exposure-light wavelength isshorter than that in a conventional case to an extent that KrF excimerlaser light (having a wavelength of 248 nm) is recently used. Atpresent, researches are in progress for use of ArF excimer laser light(having a wavelength of 193 nm) as well as F₂ laser light (having awavelength of 157 nm). In addition, researches are in progress for useof light as an exposure beam which has a wavelength of 5 to 20 nm in aso-called extreme ultraviolet (EUV) radiation region.

For a projection exposure apparatus, the illuminance of an exposure beamis required to increase to improve the throughput. In this case,however, with a short wavelength of the exposure beam, absorption of theexposure beam according to gas on the optical path (ambient atmosphere)is caused to gradually increase. Specifically, when the wavelength ofthe exposure beam enters a state of a vacuum ultraviolet (VUV) radiationregion having a wavelength of 200 nm or shorter as in the case of an ArFexcimer laser light, the absorption of the exposure beam increasesbecause of a substance (hereinbelow will be referred to as an“absorptive substance”) such as oxygen, water vapor, and carbon dioxidecontained in the ambient atmosphere of the exposure-beam optical path.When the wavelength of the exposure beam reaches a level of 180 nm orshorter, the absorption amount thereof particularly increases.

As such, when vacuum ultraviolet light is use as an exposure beam, tocause the exposure beam to be incident on a surface of a wafer atsufficient illuminance and to perform exposure with a practicalthroughput, the ambient atmosphere in most portions of the optical pathof the exposure beam needs to be replaced with a purge gas that allowsthe exposure beam to transmit. Specifically, the ambient atmosphereneeds to be replaced with gas (purge gas) such as a helium gas or anitrogen gas that has a higher transmittance for the exposure beam thana transmittance of the absorptive substance.

Because of the above, a future exposure apparatus using vacuumultraviolet light is preferably constructed such that a reticle stagesystem and a wafer stage system are individually stored in, for example,chambers having a high hermeticality. In addition, individual interlensspacings in a projection optical system are preferably formed as lensrooms having a high hermeticality, and the interiors thereof areindividually replaced with gas that allows an exposure beam to transmit.

As described above, in the conventional exposure apparatus, the stagesection, the projection optical system section, and the measuring systemare integrated. Because of this construction, a problem occurs in thatvibration of the movable section in the movable section propagatesdirectly to the measuring system, providing adverse effects to stagecontrol. In addition, a case can occur in which a part of the measuringsystem is deformed because of the movement of the movable section,causing a measurement error while it is very small.

Moreover, when a vacuum ultraviolet light such as an ArF excimer laserlight is used as exposure light, most portions of the exposure opticalpath need to be purged with nitrogen, etc.; in the conventional exposureapparatus, it is not easy to make a boundary portion, particularly,between the stage section and the projection optical system section tobe of a good hermetic construction. As such, to purge the boundaryportion with nitrogen, a problem arises in that nitrogen or the likeneeds to be fed in a chamber covering substantially the entirety of theexposure apparatus, and a large apparatus configuration is necessary. Onthe other hand, when permitting an amount of, for example, air, to bemixed in the boundary portion, although the apparatus configuration isrelatively simplified, a problem arises in that the exposure light isattenuated in the boundary portion and the light transmittances ofoptical components are reduced. The transmittances are reduced suchthat, for example, chemical reaction occurrs between small amounts oforganic components in the air and the exposure light, and the chemicalreaction causes adhesion of clouding materials, etc. onto surfaces ofoptical members.

In view of the above described problems, a first object of the presentinvention is to provide an exposure method that enables improvement incontrol precision of movable sections of stages.

A second object of the present invention is to reduce mixture ofexternal gas when a high-transmittance gas is fed into at least a partof the exposure beam optical path.

A third object of the present invention is to provide an exposure methodin which influence can be reduced of vibration occurring when a stagesystem and the like are driven, and high-precision exposure can therebybe implemented.

Furthermore, a fourth object of the present invention is to provide anexposure apparatus suitable for using the exposure method.

Still furthermore, a fifth object of the present invention is to providea manufacturing method of the exposure apparatus, and a devicemanufacturing method capable of manufacturing a high precision device byusing the exposure method or the exposure apparatus.

DISCLOSURE OF THE INVENTION

In a first exposure method according to the present invention whichilluminates a first object with an exposure beam and exposes a secondobject through a projection system with the exposure beam passed througha pattern of the first object, a first stage system which positions thefirst object, the projection system, and a second stage system whichpositions the second object are supported in such a manner thatvibration is not easily transmitted to each other.

According to the above-mentioned present invention, vibrations occurringwhen, for example, positioning and synchronous scanning are performed inthe first stage system and the second stage system are not easilytransmitted to the projection system. As such, by disposing a measuringsystem, which performs measurement for the position of a movable sectionof each of the stage systems on a basis of the projection system, in,for example, a member provided to support the projection system,high-precision measurement can be implemented for the positions of themovable section of each of the stage systems. In addition, a drivesection is controlled according to the results of the measurement,thereby improving the control precision.

In a first exposure apparatus according to the present invention whichilluminates a first object with an exposure beam from an illuminationsystem and exposes a second object through a projection system with theexposure beam passed through a pattern of the first object, the firstexposure apparatus comprises a first stage system which positions thefirst object; a second stage system which positions the second object;and support members to which the first stage system, the projectionsystem, and the second stage system are respectively connectedindependently of each other via vibration-isolating members. Accordingto the exposure apparatus, the first exposure method can be usedtherewith.

In this case, preferably, optical members in the projection system areconfigured to be substantially hermetically sealed in the projectionsystem, and there are provided a first chamber which encloses opticalmembers on the side of the first object of the illumination system, asecond chamber which encloses the first stage system, a third subchamberwhich encloses the second stage system, and flexible connection memberswhich hermetically seal portions between the first chamber, the secondchamber, the projection system and the third chamber. Thereby, outsidegas does not intrude into the optical path of the exposure beam boundaryportions between, for example, the individual chambers, hence theclouding and the like on the optical member are reduced.

In addition, preferably, when vacuum ultraviolet light having awavelength of 200 nm or shorter is used for the exposure beam, gasestransmissive for the exposure beam are respectively fed into opticalpaths inside the first chamber, the second chamber, the projectionsystem, and the third chamber. In this case, furthermore, when theboundary portions are the flexible connection members, reduction in thepurities of the gases is minimized, and the transmittance of theexposure beam is therefore highly maintained.

In a second exposure method according to the present invention, whichexposes an object with an exposure beam, two hermetic rooms in whichinside spacings are respectively substantially isolated from outside gasare disposed to be adjacent to each other on an optical path of theexposure beam and on at least a portion of a transfer passageway for theobject, a gas transmitting the exposure beam is fed into the twomutually adjacent hermetic rooms, and a spacing between the two mutuallyadjacent hermetic rooms is substantially sealed by using a coveringmember formed of a flexible filmy material.

A second exposure apparatus according to the present invention whichexposes an object with an exposure beam, comprises: two hermetic roomsin which inside spacings are respectively substantially isolated fromoutside gas are disposed to be adjacent to each other on an optical pathof the exposure beam and on at least a portion of a transfer passagewayfor the object; a gas feeding mechanism which exhausts gas in the twohermetic rooms and feeds a gas transmitting the exposure beam into thehermetic rooms; and a covering member formed of a flexible filmymaterial and provided to substantially seal a spacing between the twomutually adjacent hermetic rooms.

A third exposure apparatus according to the present invention whichexposes a second object via a first object, comprises: two hermeticrooms in which inside spacings are respectively substantially isolatedfrom an outside gas are disposed to be adjacent to each other on atleast a portion of a transfer passageway for the first object; a gasfeeding mechanism which exhausts gas in the two hermetic rooms and feedsa gas transmitting the exposure beam into the hermetic rooms; and acovering member formed of a flexible filmy material and provided tosubstantially seal a spacing between the two mutually adjacent hermeticrooms.

According to the second and third exposure apparatuses, the secondexposure method according to the present invention can be implemented.

In the exposure apparatus according to the present invention, theconnection member or the covering member preferably includes a thin-filmformed of a first material (such as ethylene vinyl alcohol, polyamide,polyimide, or polyester) having a high shielding property against gas.Thereby, the purity of gas passing through the exposure beam in theinside of each of the hermetic rooms is highly maintained.

Preferably, a thin-film formed of a second material (such as inorganicmaterial made of metal) having a low degasification property is appliedonto an inner surface of the thin-film, which is formed of the firstmaterial, of the connection members or the covering member. In thiscase, since a degasification-caused gas occurring from the firstmaterial is blocked off by the second material, gas passing through theexposure beam in each of the individual hermetic rooms is maintained ata high purity.

The arrangement may be made such that a thin-film formed of a thirdmaterial (such as polyethylene film) having a high expandability isapplied through lamination processing onto an outer surface of the firstmaterial of the connection member or the covering member; the connectionmember or the covering member is rolled into a cylindrical shape; openends of the cylindrical shape or the covering member are closed bywelding portions of the third material at two end portions of theconnection member or the covering member. There is a case where, whilethe first material exhibits a high gas-barrier property, but exhibits arelatively low expandability. However, the third material compensatesfor the expandability.

Each of first and second device-manufacturing methods according to thepresent invention includes a step of transferring a mask pattern onto asubstrate provided as an object thereof by using the second exposuremethod of the present invention or one of second and third exposureapparatuses. According to this present invention, since the secondexposure method of the present invention or one of second and thirdexposure apparatuses is used, a high-precision exposure can beimplemented by reducing influences of vibrations. Consequently, ahigh-function-level device can be manufactured.

In a first manufacturing method according to the present invention of anexposure apparatus which illuminates a first object with an exposurebeam from an illumination system and exposes a second object with theexposure beam passed through a pattern of the first object through aprojection system, the first exposure apparatus manufacturing methodperforms assembly of the illumination system, the projection system, afirst stage system which positions the first object, a second stagesystem for positions the second object, support members to which thefirst stage system, the projection system and the second stage systemare respectively connected independently of each other viavibration-isolating members according to a predetermined positionalrelationship.

Each of third and fourth device-manufacturing methods according to thepresent invention includes a step of transferring a mask pattern onto asubstrate as a second object by respectively using the first exposuremethod or the first exposure apparatus of the present invention.According to the present invention, since the first exposure method orthe first exposure apparatus of the present invention is used, ahigh-precision exposure can be implemented by improving the controlprecision for movable section of stage systems. Consequently, ahigh-function-level device can be manufactured.

A second exposure apparatus manufacturing method according to thepresent invention, in an exposure apparatus manufacturing method whichexposes an object with an exposure beam, performs assembly of twohermetic rooms in which inside spacings are respectively substantiallyisolated from outside gas are disposed to be adjacent to each other onan optical path of the exposure beam and on at least a portion of atransfer passageway for the object, a gas feeding mechanism whichexhausts gas in the two hermetic rooms and feeds a gas transmitting theexposure beam into the hermetic rooms, and a covering member formed of aflexible filmy material and provided to substantially seal a spacingbetween the two mutually adjacent hermetic rooms according to apredetermined positional relationship.

A third exposure apparatus manufacturing method according to the presentinvention, in an exposure apparatus manufacturing method which exposes asecond object via a first object with an exposure beam, performsassembly of two hermetic rooms in which inside spacings are respectivelysubstantially isolated from outside gas are disposed to be adjacent toeach other on at least a portion of a transfer passageway for the firstobject, a gas feeding mechanism which exhausts gas in the two hermeticrooms and feeds a gas transmitting the exposure beam into the hermeticrooms, and a covering member formed of a flexible filmy material andprovided to substantially seal a spacing between the two mutuallyadjacent hermetic rooms according to a predetermined positionalrelationship.

FIG. 1 is a cross sectional view showing overall configurations of aprojection exposure apparatus and an air-conditioner according to afirst embodiment of the present invention. FIG. 2 is a partially-cutawayschematic configuration view showing a gas-circulating system. FIG. 3 isa partially-cutaway schematic configuration view showing a projectionexposure apparatus according to a second embodiment of the presentinvention. FIG. 4 is a perspective view showing a filmy cover 101A. FIG.5 is a thickness-wise-enlarged transverse cross sectional view showingthe filmy cover 101A shown in FIG. 3. FIG. 6A is a perspective viewshowing a filmy cover 141 according to another embodiment of the presentinvention; and FIG. 6B is thickness-wise-enlarged transverse crosssectional view showing a part of the filmy cover 141.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinbelow, a preferred first embodiment of the present invention willbe described with reference to the accompanying drawings. The presentembodiment represents an example in which the present invention isapplied to a projection exposure apparatus employing a step-and-scanmethod by which a high-transmittance gas is fed to most portions of theexposure optical path.

FIG. 1 shows overall configurations of a projection exposure apparatusand an air-conditioner according to the present embodiment. Referring toFIG. 1, a projection exposure apparatus is disposed in a clean room on afloor F1 of a story of a semiconductor-manufacturing plant. In aso-called machine room (utility space) on a floor F2 of a downstairsthereof, there is situated the air-conditioner for feeding air regulatedin temperature into peripheral portions of the projection exposureapparatus on the upstairs. On the floor F2, there is situated agas-circulating apparatus for circulating the high-transmittance gas tothe exposure optical paths of the projection exposure apparatus (referto FIG. 2). In this way, the apparatus that tends to producing dust andto be a vibrating source is situated on the floor different from thefloor whereon the projection exposure apparatus is situated. Thisarrangement enables the cleanliness in the clean room, in which theprojection exposure apparatus is provided, to be substantially high.Furthermore, the arrangement enables a reduction in the influence ofvibration to the projection exposure apparatus. In this configuration, alight-source system 61 (described below) may be situated on the floorF2.

In the clean room, the projection exposure apparatus is situated that isconfigured to include the light-source system 61, an illumination system62, a reticle stage system 63, a projection optical system PL, and awafer stage system 64. The light-source system 61 and the illuminationsystem 62 together constitute an illumination optical system. To supportthe projection exposure apparatus, columns 8A and 8B are securely fixedonto the floor F1, in which upper portions of the columns 8A and 8B areconnected through a ceiling plate 8C. The floor F1 and the columns 8Aand 8B in the present embodiment (shown in FIG. 1) correspond to supportmembers of the present invention. However, as disclosed in a below-described second embodiment (shown in FIG. 3), the projection exposureapparatus may be placed on a floor via a base member (102C).Alternatively, a base table 39 on which the wafer stage system 64 isplaced may be hanged from the columns 8A and 8B through a frame. Thebase member and the columns 8A and 8B in the former case correspond tothe support members of the present invention; and the columns 8A and 8Bin the latter case correspond to the support member of the presentinvention.

The light-source system 61 and the illumination system 62 are storedrespectively in a box-like subchamber 1 having a high hermeticality andsecond a second subchamber 6. The first subchamber 1 is disposed on thefloor F1 via vibration-isolating blocks 2A and 2B. The second subchamber6, in which the illumination system 62 is stored, is directly fixed ontoan upper portion of the column 8A and a portion of the ceiling plate 8C.The wafer stage system 64 is disposed on the floor F1 between thecolumns 8A and 8B via vibration-isolating blocks 40A and 40B. Each ofthe vibration-isolating blocks 40A and 40B is an activevibration-isolating mechanism formed by combining, for example, an airdamper and electromagnetic damper employing a method using a voice coilmotor (VCM). A lens housing for the illumination system 62 may be storedin the second subchamber 6 as a housing. However, the hermeticality ofthe lens housing for the illumination system 62 may be increased, andthe lens housing may be used as the second subchamber 6 (whichcorresponds to a first chamber of the present invention). The essentialis that the subchambers are not limited by the housings.

In a portion between columns 8A and 8B, a support plate 32 is placed onan upper portion of the wafer stage system 64 via a vibration-isolatingmechanisms 35A and 35B. The projection optical system PL is disposed onan opening in a central portion of the support plate 32. The reticlestage system 63 is disposed on an upper portion of the projectionoptical system PL between the columns 8A and 8B via vibration-isolatingmechanisms 24A and 24B. For the individual vibration-isolatingmechanisms 35A, 35B, 24A, and 24B, for example, a horizontallyexpandable air damper or hydraulic damper is usable. Thus, in thepresent embodiment, the reticle stage system 63 is provided as a firststage system, the projection optical system PL is provided as aprojection system, and the wafer stage system 64 is provided as a secondstage system. The members are individually supported by the firstsubchamber 1 and the columns 8A and 8B in a state in which vibrationsthereof are not easily propagated to each other. The illumination system62 almost does not cause vibrations; hence, even when it is directlyfixed to, for example, the column 8A, no adverse effects occur. However,at least a portion of the illumination system 62 may be disposed to beisolated away from the columns 8A and 8B. For example, the configurationmay be arranged such that the illumination optical system is separatedinto two with a below described fixed blind 15A, the fixed blind 15A andthe optical system situated closer than the fixed blind 15A are providedon the main unit side (columns 8A and 8B), and other members areprovided on a different frame. In this case, movable or replaceableoptical devices (such as a movable blind 15B) are preferably disposed onthe different frame. In addition, on the side of the main unit, a sensoris preferably provided that detects the relative positional relationshipbetween at least a portion of the separated illumination system 62 andcomponents (such as the reticle stage system 63 and projection opticalsystem PL).

The reticle stage system 63 and the wafer stage system 64 are stored inhigh-hermeticality box-like third subchamber 23 and fourth subchamber24, respectively. Spacings between individual optical members in theprojection optical system PL are substantially hermetically enclosed ashermetic rooms. In the present embodiment, while an ArF excimer laser(having a wavelength of 193 nm) is used as an exposure beam, such vacuumultraviolet light is substantially absorbed by oxygen. In considerationof the above, in the present embodiment, to prevent attenuationoccurring in the exposure-beam optical path, a nitrogen gas (N₂) is fedinto the exposure-beam optical path as a gas that has a hightransmittance and that is chemically stable. As an alternative gas thathas a high-transmittance and that is chemically stable, for example,helium gas (He) may be used. However, since nitrogen is more inexpensivethan helium, the present embodiment uses the nitrogen gas.

In the present embodiment, a gas-circulating system (described below) isprovided to purge the inside of the individual first to fourthsubchambers 1, 6, 23, and 42 with high-purity nitrogen gas. In addition,high-purity nitrogen gas is fed to purge the inside of the hermeticrooms in the projection optical system PL. Furthermore, bellows 25, 36,and 43, such as stainless steel bellows, which have flexibility of acertain level with a deformation amount that does not increase so much,are connected, respectively, to a boundary portion between the secondsubchamber 6 and the third subchamber 23, a boundary portion between abottom surface of the reticle stage system 63 and an upper portion ofthe projection optical system PL, and a boundary portion between a lowerportion of the projection optical system PL and the fourth subchamber42. For the bellows 25, 36, and 43, a material (such as metal) having alow degasification property is preferably used. Alternatively, aTeflon-coated material may be used for the bellows 25, 36, and 43. Stillalternatively, a material such as synthetic resin or synthetic rubbermay be used. Also in this case, degasification- preventing coating ispreferably applied. With these bellows 25, 36, and 43, the boundaryportions are substantially hermitically enclosed, and substantially, theentirety of the exposure-beam optical path is hermetically enclosed. Asa result, the configuration allows almost no outside impure gas tointrude into the exposure-beam optical paths, and hence the attenuationamount of the exposure beam is significantly reduced.

Hereinbelow, the configuration of the projection exposure apparatusaccording to the present invention will be described. In the firstsubchamber 1, an exposure light source 3, a beam-matching unit 4 (BMU),and a pipe 5 are disposed. The exposure light source 3 is formed of anArF excimer laser light source. The BMU 4 includes a movable mirror usedto perform positional matching for the optical path in the field to theexposure main unit section. The pipe 5 is formed of a light-shieldingmaterial, and it transmits the exposure beam. At the time of exposure,ultraviolet pulse light IL emitted from the exposure light source 3 asan exposure beam having a wavelength of 193 nm passes through the insideof the BMU 4 and the pipe 5, and enters the second subchamber 6. In thesecond subchamber 6, the ultraviolet pulse light IL passes through abeam-shaping optical system, and is led to be incident on a fly's eyelens 11 that functions as an optical integrator (homogenizer). Thebeam-shaping optical system is formed to include a variable attenuationdevice 9 that functions as a light attenuator, and lens systems 10A and10B. On an exit surface of the fly's eye lens 11, an aperture diaphragmsystem 12 of an illumination system is installed. The aperture diaphragmsystem 12 changes the illumination condition in various ways.

Thus, the ultraviolet pulse light IL emitted from the fly's eye lens 11passes through the predetermined aperture diaphragm, and is then led tobe incident on a fixed illumination view-field aperture 15A (fixedblind) and a movable blind 15B through a reflection mirror 13 and acondenser lens system 14. The fixed illumination view-field aperture 15A(fixed blind) includes a slit-like opening section in a reticle blindmechanism 16. The movable blind 15B functions to make the width of anillumination view-field region in a scan direction to be variableindependently of the fixed blind 15A. The movable blind 15B is used toimplement reductions in scan-directional movement stroke of the reticlestage as well as in width of a light-shielding zone of a reticle R.

The ultraviolet pulse light IL shaped as a slit through the fixed blind15A of the reticle blind mechanism 16 radiates a slit-like illuminationregion in a circuit pattern region of the reticle R in a uniformintegrity distribution. The light IL is thus radiated through an imaginglens system 17, a reflection mirror 18, and a primary condenser lenssystem 19. In the present embodiment, the illumination system 62 isconfigured to include optical members provided in the portion from thevariable extinction device 9 to the primary condenser lens system 19.

Under the ultraviolet pulse light IL, a circuit-pattern image in theillumination region of the reticle R is transferred onto a slit-likeexposure region of a resist layer on a wafer W through the projectionoptical system PL. The exposure region is positioned in one of aplurality of shot regions on the wafer W. The projection optical systemPL of the present embodiment is a dioptric system. However, availabilityis limited for glass materials capable of transmitting the ultravioletlight having the short wavelength is limited. As such, for theprojection optical system PL, either a catadioptric system or areflection system may be used to increase the transmittance of theultraviolet pulse light IL. Hereinbelow, a description will be made on abasis of X, Y, and Z axes as shown in the figure. The Z axis isestablished parallel to an optical axis AX of the projection opticalsystem PL. The X axis established parallel to the sheet face of FIG. 1in a plane that is perpendicular to the Z axis (substantially horizontalplane in the present invention). The Y axis established perpendicular tothe sheet face of FIG. 1.

The reticle R is adsorbed and held on a reticle stage 20. The reticlestage 20 is layered to be uniformly movable on a reticle base 21 in theX direction (scan direction). In addition, the reticle R is uniformlymovable in the X-direction, the Y direction, and the rotationaldirection. A movable mirror (not shown) is fixedly arranged, and areference mirror 22 is also fixedly arranged on an upper side face ofthe projection optical system PL. A reticle-dedicated interferometermain body portion 33 is fixedly arranged on the support plate 32 thatsupports the projection optical system PL. An upper portion of thereticle interferometer main body portion 33 reaches an interior of thethird subchamber 23 through an opening of the reticle base 21. Acircumferential opening of the interferometer main body portion 33 isseal-blocked with, for example, a resin material that has elasticity anda low degasification property. A laser beam is radiated from theinterferometer main body portion 33 to the movable mirror of the reticlestage 20 and to the reference mirror 22 of the projection optical systemPL. On the basis of the reference mirror 22 (projection optical systemPL), the interferometer main body portion 33 measures two-dimensionalposition of the reticle stage 20 and the rotational angle thereof, andfeeds the measurement result to a drive controller (not shown). Thus,the reticle stage system 63 is configured to include the reticle stage20 and the reticle base 21. The interferometer main body portion 33corresponds to a first measuring system of the present invention.

The wafer W is adsorbed and held on a wafer holder 37. The wafer holder37 is fixedly arranged on a wafer stage 38, and the wafer stage 38 isdisposed on the base table 39. The wafer stage 38 employing an autofocusmethod controls a focus position (position in the Z direction) of thewafer W and a tilt angle thereof. Thereby, the wafer stage 38 aligns thesurface of the wafer W with an image plane of the projection opticalsystem PL. In addition, the wafer stage 38 performs equal-velocityscanning of the wafer W in the X direction as well as stepping thereofin the X and Y directions. In addition, a movable mirror (not shown) isfixedly arranged on a side face of the wafer stage 38, and a referencemirror 41 is fixedly arranged on a lower side face of the projectionoptical system PL. A wafer-dedicated interferometer main body portion 34is fixedly arranged onto the support plate 32 that supports theprojection optical system PL. A lower portion of the interferometer mainbody portion 34 reaches an upper portion of the base table 39 in thefourth subchamber 42. A gap between an opening of the fourth subchamber42 and the interferometer main body 34 is seal-blocked with, forexample, a resin material that has elasticity and a low degasificationproperty.

A laser beam is radiated from the interferometer main body portion 34 tothe movable mirror of the wafer stage 38 and to the reference mirror 41of the projection optical system PL. On the basis of the referencemirror 41 (projection optical system PL), the interferometer main bodyportion 34 measures two-dimensional position of the wafer stage 38 andthe rotational angle (including a yawing amount, a pitching amount, anda rolling amount) thereof, and feeds the measurement result to a drivecontroller (not shown). The reticle stage system 64 is configured toinclude the wafer holder 37, the wafer stage 38, and the base table 39.The interferometer main body portion 34 corresponds to a secondmeasuring system of the present invention. Preferably, measuring sensorsare provided on the support plate 32 as a measuring system. For example,the measuring system preferably includes a sensor for measuring the gapand the tilt angle in the Z direction of the reticle base 21 withrespect to the projection optical system PL, and a sensor for measuringthe gap and the tilt angle in the Z direction of the base table 39 withrespect to the projection optical system PL. In a scan-exposureoperation, the reticle R is scanned via the reticle stage 20 for anillumination region of the ultraviolet pulse light IL in the +Xdirection (or in the −X direction) at a velocity Vr. In synchronizationwith the scanning, the wafer W is scanned for an exposure region via thewafer stage 38 in the −X direction (or in the +X direction) at avelocity of β·Vr (β represents the projection magnification from thereticle R to the wafer W). The scan directions for the reticle R and thewafer W is arranged to oppose each other for the reason that theprojection optical system PL performs reverse projection.

In the present embodiment, a box-like chamber 7 that is large as a wholeis used to house the columns 8A and 8B, the reticle-side portion of thesecond subchamber 6 in which the illumination system 62 is housed, thethird subchamber 23, the projection optical system PL, and the fourthsubchamber 42. On an upper portion of the chamber 7,temperature-regulated air is fed from an air-conditioner 52 provided onthe floor F2 of the downstairs. The air that has thus been fed thenpasses through a diffusion section 49 and enters a filter section 50that includes a dust filter, such as a HEPA filter (high efficiencyparticulate air-filter), and a chemical filter for removing a smallamount of organic substance. Then, the air passed through the filtersection 50 is led flow downwardly around the second to fourthsubchambers 6 to 42, and is discharged from an opening (not shown)provided in a bottom portion of the chamber 7. Thereby, the temperaturearound the second to fourth subchambers 6 to 42 of the presentembodiment is maintained substantially to be constant.

A load-lock chamber 26 is provided in a portion from an end portion onthe reticle base 21 to an opening portion of the column 8B and anopening portion of the chamber 7. The load-lock chamber 26 deliversreticles between the reticle stage system 63 and the outside and to holdan in-process reticle substantially in a complete hermetic state.Furthermore, a reticle loader system 28 is fixed onto a side face of thecolumn 8B and onto a support plate 27 that has passed through theopening of the chamber 7. A fifth subchamber 29 is provided such as toenclose the reticle loader system 28. Shuttable doors are individuallydisposed on faces opposing the reticle loader system 28 and the reticlebase 21, and the peripheral portions of the load-lock chamber 26 arehermetically enclosed.

A load-lock chamber 44 is provided in a portion from an end portion onthe base table 39 to the opening portion of the column 8B and theopening portion of the chamber 7. The load-lock chamber 44 deliversreticles between the wafer stage system 64 and the outside. A waferloader system 45 is provided so as to be in contact with a side face ofthe load-lock chamber 44 to deliver wafers between itself and an atransfer line (not shown). The wafer loader system 45 is fixed onto thefloor F1. The sixth subchamber 46 is provided to enclose the waferloader system 45. A pair of shuttable doors is disposed for theload-lock chamber 44. Temperature-regulated air is fed from theair-conditioner 52 to upper portions of the respective fifth subchamber29 and sixth subchamber 46 via a pipeline 31 and a pipeline 48. The airfed thereto passes through filter sections 30 and 47. The air is led toflow in lower proportions around the individual reticle loader system 28and wafer loader system 45, and is then exhausting.

As described above, in the present embodiment, althoughtemperature-regulated air flows outside of the second to fourthsubchambers 6 to 42, the hermeticality of the second to fourthsubchambers 6 to 42 is high. Furthermore, the bellows 25, 36, and 43 areprovided. Consequently, almost no air intrudes into the optical path ofthe ultraviolet pulse light IL, and the use efficiency of theultraviolet pulse light IL can be highly maintained. However, in aconfiguration in which the hermeticality of subchambers surroundingindividual portions of a projection exposure apparatus is low, an inertgas having a high transmittance, such as a nitrogen gas, should be fedto flow in the entirety of the chamber 7. In this case, a problem arisesin that an expensive temperature-regulating facility needs to beprovided, thereby increasing operation costs.

In addition, in the present embodiment, temperature-regulated air is fedalso into peripheral portions of the reticle loader system 28 and thewafer loader system 45. Furthermore, the load-lock chamber 26 and theload-lock chamber 44 are individually disposed in the portion betweenthe fifth subchamber 29 and the sixth subchamber 46 in the portionbetween the third subchamber 23 and the load-lock chamber 44. As such,for example, when replacing the reticle R, the right door is shut, andthe reticle R is stored in the load-lock chamber 26; and after the rightand left doors are air-tightly shut, the reticle R is replaced withanother reticle. Thereafter, the right and left doors of the load-lockchamber 26 are shut, an exhausting unit (described below) is used toexhaust the inside, and the nitrogen gas is then hermetically enclosed.Subsequently, the left door is opened, and the reticle in the load-lockchamber 26 is loaded onto the reticle stage 20. Thereby, intrusion ofair on the side of the reticle loader system 28 into the thirdsubchamber 23 is prevented. By performing similar operations, intrusionof air on the side of the wafer loader system 45 into the fourthsubchamber 42 is prevented. With the load-lock chambers 26 and 44 eachprovided as a delivery-dedicated chamber, temperature-regulated air canalso be led to flow around the reticle loader system 28 and the waferloader system 45.

In the above-described present embodiment, preferably, stainless steelmaterials are used for, or alternatively, Teflon coating is applied tomaterials of members, such as the subchamber 6, 23, and 42, or membersdisposed therein, for example, portions of the interferometer main bodyportions 33 and 34, to minimize degasification.

Hereinbelow, a configuration of a gas-circulating system in theprojection exposure apparatus of the present embodiment will bedescribed referring to FIG. 2. In FIG. 2, the same reference numeralsare used to represent portions corresponding to those shown in FIG. 1,and descriptions thereof are omitted herefrom.

FIG. 2 shows the gas-circulating system of the projection exposure unitaccording to the present embodiment. Referring to FIG. 2, on the floorF2 of the downstairs of the floor F1, there are provided an exhaustingunit 65 including a vacuum pump, a nitrogen-gas collecting unit 66, astorage unit 67 for storing high-purity nitrogen in the form of liquidnitrogen or the like, and a temperature-regulating unit 68 forregulating the temperature of nitrogen gas and for feeding the gas tothe outside. The exhausting unit 65 selectively absorbs gas to be in avacuum state via two exhausting pipelines 70 and 72, and feeds theadsorbed gas into the collecting unit 66 via a pipeline 74. Thecollecting unit 66 is configured to include an absorbing section, aseparating section, a storage section, and a feeding section. Theabsorbing section absorbs gas from an exhausting pipeline 73. Theseparating section separates nitrogen gas from the gas fed from theabsorbing section and gas collected via the pipeline 74. The storagesection temporarily stores the separated nitrogen gas. The feedingsection feeds the stored gas to the temperature-regulating unit 68 via apipeline 75. The storage unit 67 feeds the stored nitrogen as needsarises to the temperature-regulating unit 68 through a pipeline 76 towhich a valve V22 is connected. The temperature- regulating unit 68includes a temperature control section, a gas-blowing section, and afilter section 77. The temperature control section controls thetemperature of gas (a nitrogen gas, in this particular case) fed via thepipelines 75 and 76. As needs arises, the gas-blowing section blows thegas fed from the temperature control section. The filter section 77includes a HEPA filter and a chemical filter for removing dust from theblown gas. The air passed through the filter section 77 is fed into agas-feeding pipe 69.

The filter section 77 removes impurities (contaminants) in addition todust and moisture. Impurities to be removed by the filter section 77include substances that adhere to the exposure light source 3, opticalelements of the illumination optical system, and the projection opticalsystem PL to thereby cause the elements to be cloudy. The impurities tobe removed also include substances that flow along the optical path ofthe exposure beam and causes variations in, for example, thetransmittance (illumination) or the illumination distribution of theillumination optical system and the projection optical system PL. Inaddition, the impurities to be removed include substances that adhereonto a surface of the wafer W (resist) to thereby cause apostdevelopment pattern image to vary. A usable filter for a part of thefilters in the filter section 77 is an active-carbon filter (forexample, “GIGASORB” (brand name) produced by Nitta Corp.), a zeolitefilter, or a filter formed by combining the filters. The filters removesilicon organic substances, such as siloxanes (substance containing achain of Si—O as a base) or silazanes (substance containing a chain ofSi—N as a base). The collecting unit 66 and the temperature-regulatingunit 68 in FIG. 2 correspond to a gas-circulating unit of the presentinvention.

The projection exposure apparatus on the floor F1 is configured asfollows. An end portion of the gas-feeding pipe 69 extending from thedownstairs branches to a first branch pipe having a valve V1 to aseventh branch pipe having a valve V7. The first branch pipe having thevalve V1 is connected to a first chamber 1 (light-source system 61). Asecond branch pipe having the valve V2 is connected to a secondsubchamber 6 (illumination system 62). The third branch pipe having thevalve V3 is connected to a third subchamber 23 (reticle stage system63). The fourth branch pipe having the valve V4 is connected to ahermetic room of the projection optical system PL. The fifth branch pipehaving the valve V5 is connected to a fourth subchamber 42 (wafer stagesystem 64). The sixth branch pipe having the valve V6 and seventh branchpipe having the valve V7 are connected to load-lock chambers 26 and 44,respectively. As such, in the configuration, according to a blowingoperation for gas from the temperature-regulating unit 68 and aselective on/off operation of one of the valves V1 to V7, transmissivegas (nitrogen gas in this particular case) can be appropriately fed topurge any one of the hermetic rooms of first subchamber 1 to theload-lock chamber 44 for the exposure beam.

The first subchamber 1 to the third subchamber 23, the hermetic room ofthe projection optical system PL, and the fourth subchamber 42 areindividually connected to an exhaust pipeline 71 through branch pipesindividually having valves V11 to V15. As such, according to a selectiveon/off operation of valves V20 or 21, gas in the first subchamber 1 tothe fourth subchamber 42 can be exhausted by using one of the exhaustingunit 65 and the collecting unit 66. The load-lock chambers 26 and 44 areindividually connected to an exhausting pipeline 70 through branch pipesindividually having valves V16 and V17. As such, according to an on/offoperation of the valves 16 and 17, gas in each of the load-lock chambers26 and 44 can be appropriately exhausted using the exhausting unit 65 toan extent that each of the load-lock chambers 26 and 44 becomes in avacuum state.

A pressure sensor and a impurity sensor (an oxygen concentration metermay be used) for detecting the concentration of impurities such asoxygen are provided in each of the first subchamber 1 to the load-lockchamber 44. When the detection result of the impurity sensor exceeds atolerance, it is preferable that gas in the corresponding hermetic roomor chamber is exhausted, and a transmissive gas is fed into thecorresponding chamber and hermetic room to set the pressure detected bythe pressure sensor to a predetermined reference pressure (for example,a level of the atmospheric pressure).

Hereinbelow, a description will be made regarding example operations forcirculating a transmissive gas into individual portions of theprojection exposure apparatus. When the first to fourth subchambers 1 to42 are full of air at the time of, for example, operation commencementof the exposure apparatus, the valves V1 to V5 and V21 are controlled toshut, and valves V11 to V15 and V20 are controlled to open. Thereby, andthe air is abruptly exhausted. After exhausted amount has reached acertain level, the valves V11 and V15 are controlled to shut, valves V1to V5 are controlled to open, and a transmissive gas is thereby fed fromthe temperature-regulating unit 68 into the first to fourth subchambers1 to 42. Then, exhaustion and feed operations are iterated using theexhausting unit 65 until the concentration of impurities (such asoxygen) reaches a level of the tolerance.

After the impurity concentration has reached a level of the tolerance,the valve V20 is controlled to shut, and exposure operation iscontrolled to commence. During the exposure operation, when the impurityconcentration in one of the first to fourth subchambers 1 to 42 hasincreased, a certain amount of gas is exhausted through the collectingunit 66 to replace the gas therein. Then, purging with the transmissivegas is done through the temperature-regulating unit 68. These operationsenable the transmissive-gas consumption as well as operation costs to bereduced.

When the reticle or the wafer is to be replaced, as already described,the reticle or a wafer to be subsequently used is stored in theload-lock chamber 26 or 44, and the right and left doors are locked. Inthis state, abrupt exhaustion is performed using the exhausting unit 65,and concurrently, gas is fed into the rooms from thetemperature-regulating unit 68. These operations enable the amount ofimpurity intrusion from the reticle loader system or the wafer loadersystem into the side of the optical path to be substantially removed.Thus, the configuration has an advantage in that the exposure-stepthroughput almost does not decrease.

In the arrangement of the present embodiment, the same type of gas(nitrogen gas in this particular case) that is transmissive and stableis fed into the first to fourth subchambers 1 to 42. However, thearrangement may be modified such that a different type of transmissiveand stable gas, for example, as a helium gas, is fed into portions asthe interior portion of the projection optical system PL for whichstability in optical property is particularly required. Although thehelium gas is expensive, it has an excellent property in radiationeffects. The thermal conductivity of the helium gas is six times higherthan that of the nitrogen gas. In addition, since the helium gas has aless-variable refraction index, it exhibits advantages in, for example,image-forming property. In this view, using the helium gas prevents theincrease in the operation costs.

According to the arrangement of the present embodiment, in thecollecting unit 66 shown in FIG. 2, the collected nitrogen may becompressed using a compressor to a pressure level of from 100 to 200atmosphere. Alternatively, the arrangement may be modified such that aliquefying unit employing a turbine is used to liquefy the collectednitrogen, and the liquefied nitrogen is stored in an inner container.

In the arrangement of the present embodiment, most portions of theillumination optical system are housed in the second subchamber 6, and aportion of the second subchamber 6 is provided in the chamber 7.However, the arrangement may be modified such that the entirety of, forexample, the second subchamber 6 is housed in the chamber 7. Themodified arrangement enables the amount of impurities in the secondsubchamber 6 to be reduced.

In the arrangement of the above-described present embodiment, a singletype of gas (rare gas such as nitrogen gas, helium gas, or neon gas) isfed to each of the first to fourth subchambers 1 to 42. However, a gascomposed by mixing nitrogen gas and helium gas at a predetermined ratiomay be fed into the individual subchambers. In this case, mixingelements are not limited to the nitrogen and helium gases; and a mixedgas with a different element, such as neon gas or hydrogen gas, may beused.

In addition, a transmissive and chemically stable gas may be used bychanging the purity (concentration) for at least one of the first tofourth subchambers 1 to 42, the projection optical system PL, andload-lock chambers 26 and 44 and other configuration members. That is,the same type of gas may be used by changing the concentration ofimpurities (such as oxygen, water vapor, and organic substances) for themembers. Alternatively, for the configuration members separated intothree or more groups, the same type of gas may be used by changing thepurity (impurity concentration).

The configurations, the supporting methods therefor, and the like arenot limited to those of the individual units, such as the projectionoptical system, the reticle stage system, and the wafer stage system inthe present embodiment (in FIGS. 1 and 2). Any configurations andsupporting methods may be used as long as they are supported not tocause vibrations thereof to be propagated to each other.

The bellows 25, 36, and 43 need not be provided for all theabove-described connected portions. The bellow may be provided only forone of the connected portions. In addition, bellows as mentioned abovemay be provided for connected portions when the illumination opticalsystem or the projection optical system is separated and stored into aplurality of hermetic rooms. This applies as well to a case in which thereticle loader system 28 or the wafer loader system 45 is separated andstored into a plurality of hermetic rooms. In addition, bellows may beprovided for connected portions between a lens housing provided forhousing portions of the optical systems (for example, the interferometermain body portions 33 and 34, a reticle alignment system, a waferalignment system, and an autofocus sensor), which are provided aroundthe third subchamber 23 or the fourth subchamber 42, and thecorresponding subchambers. Moreover, bellows may be provided forconnected portions between the pipelines provided for feeding andexhausting purge gas and the above-described individual subchambers andthe projection optical system.

In the above-described embodiment, although the ArF excimer laser isused as the exposure beam, a different laser is usable. A usable laseris any one of, for example, a KrF excimer laser (having a wavelength of248 nm), an F₂ laser (having a wavelength of 156 nm), a Kr₂ laser(having a wavelength of 147 nm), and an Ar₂ laser (having a wavelengthof 126 nm). The present invention is applicable also to exposureapparatuses having a light source of the different laser. However, in anexposure apparatus using, for example, a KrF excimer laser, air in aprojection optical system need not be replaced with a gas such asnitrogen gas or helium gas. In this case, it is sufficient to replaceonly air in an optical source of the KrF excimer laser and in anillumination optical system with, for example, a nitrogen gas.

Furthermore, the present invention is applicable to a configurationusing one of the following optical beams as an exposure beam instead ofthe excimer laser. The beams are those having wavelengths of, forexample, 248 nm, 193 nm, and 157 nm, and harmonics of a solid statelaser such as a YAG laser having a vibrational spectrum in the vicinityof each of the wavelengths.

Hereinbelow, a second embodiment of the present invention will bedescribed with reference to the drawings. In the present embodiment, thepresent invention is applied to a projection exposure apparatus thatemploys a step-and-scan method in which vacuum ultraviolet light is usedas an exposure beam.

In the exposure apparatus of the above-described first embodiment,lenses in the reticle stage system, the wafer stage system, and theprojection optical system are housed in the hermetic units. In addition,spacings between the adjacent hermetic units are hermetically coveredusing the below mechanisms formed of metal or the like.

However, in the configuration using metal below mechanisms having a highrigidity, a case can occur in which the image-forming property of theprojection optical system is lowered. This problem can occur for thereason that, for example, vibrations occurring when the wafer stagesystem, the reticle stage system, and the like are driven, anddeformations of the hermetic units or the like caused by shift in thecenter of gravity (unbalanced loads) in the stage systems are propagatedto the projection optical system through the below mechanisms. Inaddition, another problematic case can occur in which influences ofvibrations and unbalanced loads occurring from the stage systems arepropagated to, for example, the reticle interferometer and the alignmentunits, thereby reducing the measurement precision thereof. Theinfluences of vibrations can be reduced to a certain extent throughadjustment of the rigidity of the below mechanisms. However, preferably,such influences are further reduced.

To minimize the exposure of the inside of, for example, a reticle stagesystem and a wafer stage system, to the outside, researches are inprogress for the provision of metal below mechanisms, for example,between a reticle loader system and a main body of an exposure apparatusand between a wafer loader and the main body of the exposure apparatus.Also in this case, however, a problematic case can occur in whichinfluences of vibrations and unbalanced loads are propagated to the mainbody of the exposure apparatus, thereby lowering, for example, theimage-forming property of a projection optical system and themeasurement precision of a reticle interferometer and the like.Vibration-isolating mechanisms can be provided also for, for example,the reticle loader system and the wafer loader system to reducereductions in, for example, the image-forming property and themeasurement precision of the interferometer because of vibrations andunbalanced loads that occur in the loader systems. However, problems canarise in that influences of vibrations remain, and costs formanufacturing the exposure apparatus increase. In view of theseproblems, in the second embodiment, a description will be givenregarding the example in which the vibration-isolating property isfurther improved.

FIG. 3 is a schematic configuration view showing a projection exposureapparatus according to the present embodiment. Referring to FIG. 3,although the projection exposure apparatus uses the source of ArFexcimer laser light (having a wavelength of 193 nm), other light sourcesare usable. Usable light sources include an F₂ laser light source(having a wavelength of 157 nm), a Kr₂ laser light source (having awavelength of 146 nm), a harmonics-generating unit for generating a YAGlaser, and a light source such as a semiconductor-laserharmonics-generating unit for generating vacuum ultraviolet light (lighthaving a wavelength of 200 nm or shorter in the present embodiment).However, also when, for example, a KrF excimer laser light source(having a wavelength of 248 nm) and mercury lamp (i-ray, etc.) is usedfor the exposure beam, the present invention can be used to increase thetransmittance of the exposure beam.

Vacuum ultraviolet light is substantially absorbed by absorptivesubstances, such as oxygen, water vapor, hydrocarbon-based gas (forexample, carbon dioxide), organic substances, and halogenide, which areincluded in the normal atmosphere. In view of the above, in aconfiguration using the vacuum ultraviolet light for the exposure beamas in the present embodiment, to prevent attenuation of the exposurebeam, the gas concentration of the absorptive substances (impurities)needs to be reduced lower than or equal to a range of from 10 to 100ppm. In the present embodiment, however, gas located in the optical pathof the exposure beam is replaced with a gas transmitting the exposurebeam, i.e., a gas such as a nitrogen (N₂) or a rare gas (whichhereinbelow will be called “purge gas”) formed of helium (He), neon(Ne), argon (Ar), krypton (Kr), xenon (Xe), or radon (Rn). The purge gashas a high-transmittance and chemically-stable property) and is composedby significantly removing absorptive substances.

While the nitrogen gas can be used as the gas (purge gas) transmittingthe exposure beam even in a VUV radiation region when the wavelengththereof is up to a level of 150 nm, it works as an absorptive substancefor light of which the wavelength is a level of 150 nm or shorter. Assuch, a rare gas is preferably used for the purge gas for an exposurebeam having a wavelength of 150 nm or shorter. Among rare gases, ahelium gas is preferably used in view of properties such as a stabilizedrefraction index and a high thermal conductivity, and the like. However,since helium is expensive, a different rare gas may be used whenconsidering the operation costs and the like to be important. For thepurge gas, not only one type of gas, but also a mixed gas as thatcomposed by mixing nitrogen and helium at a predetermined ratio may beused.

In the present embodiment, considering the properties such as astabilized refraction index (stabilized image- forming property) and ahigh thermal conductivity to be important, a helium gas is used for thepurge gas. As such, a feeding/exhausting mechanism 113 is disposed. Thefeeding/exhausting mechanism 113 feeds a high-purity purge gas into theexposure apparatus of the present embodiment and a plurality of hermeticrooms associated with the projection exposure apparatus in a machineroom located in a downstairs of a floor on which the projection exposureapparatus is disposed. In addition, the feeding/exhausting mechanism 113collects the gas flowed in the hermetic rooms to enable the gas to bereused.

Hereinbelow, the configuration of the projection exposure apparatusaccording to the present embodiment will be described in more detail. Amain body portion of the projection exposure apparatus of the presentembodiment is situated on a base member 102C. A first frame 102A isdisposed on the base member 102C and is shaped substantially as a gateincluding four or three leg portions (columns). An illumination opticalsystem of the present embodiment is configured to include opticalmembers such as an exposure light source and an optical integrator (suchas a uniformizer or homogenizer). The optical members excluding theexposure light source are housed in a box-like first subchamber 103having a highly hermeticality, and the first subchamber 103 is providedon an upper portion of the first frame 102A. An exposure beam (exposurelight) formed of a pulse laser having a wavelength of 193 nm is emittedfrom the exposure light source (not shown) in the illumination opticalsystem. The emitted exposure beam illuminates a pattern region of apattern surface (lower surface) of a reticle R that is used as a mask.The exposure beam passed through the reticle R forms an image formed byreducing the pattern of the reticle R at a projection magnification β(β=¼, ⅕, etc.). The image is formed on a wafer W (substrate) through aprojection optical system 104 provided as a projection system. The waferW is a disc-like substrate, such as a silicon semiconductor or a SOI(silicon on insulator), and a photoresist is applied thereon. Theindividual reticle R and wafer W correspond to exposure-targetsubstances of the present invention.

As in the case disclosed in Japanese Patent Application No. 10-370143 orNo. 11-66769 for example, a cylindrical catadioptric system and acylindrical dioptric system may be used for the projection opticalsystem 104. The catadioptric system is configured to include a pluralityof dioptric lenses and two concave lenses each having an opening near anoptical axis. These lenses are arranged along the optical axis. On theother hand, the dioptric system is configured to include dioptric lensesarranged along one optical axis. Alternatively, a double-cylindricalcatadioptric system may be used for the projection optical system 104.Hereinbelow, the configuration of the present embodiment will bedescribed on a basis of X, Y, and Z axes as shown in the figure. The Zaxis is established parallel to an optical axis of the projectionoptical system 104. The X axis established parallel to the sheet face ofFIG. 3 in a plane that is perpendicular to the Z axis. The Y axisestablished perpendicular to the sheet face of FIG. 3. In this case, anillumination region on the reticle R is formed as a slit that is a longand narrow along the X direction, and the scanning direction for thereticle R and the wafer W during exposure is the Y direction.

The reticle R is held on a reticle stage 107 b via a reticle holder 107a. The reticle stage 107 b is driven according to a linear motor methodto continually move on a reticle base 107 c in the Y direction (scandirection), and concurrently, to finely adjust the position of thereticle R within an XY plane. When the reticle stage 107 b moves in theY direction, the reticle base 107 c moves on a base member 121 in thedirection opposing the movement direction of the reticle stage 107 b insuch a manner as to satisfy the law of conservation of momentum.Thereby, the reticle base 107 c inhibits vibrations that can occur whenthe reticle stage 107 b moves. The base member 121 is supported onsupport plates (shown in two portions in FIG. 3) provided on fourintermediate portions (which may be three portions) of the first frame102A via vibration-isolating members 123A and 123B. Each of thevibration-isolating members 123A and 123B is an activevibration-isolating unit formed by combining an air damper (which mayalternatively be a hydraulic damper) and an electromagnetic actuatorsuch as a VCM (voice coil motor). A reticle stage system RST isconfigured to include the reticle holder 107 a, the reticle stage 107 b,and the reticle base 107 c. The reticle stage system RST is housed in abox-like second subchamber 108 (reticle room) having a highhermeticality.

A second frame 102B substantially shaped as a gate is disposed inside ofthe first frame 102A on an upper surface of the base member 102C viavibration-isolating members 124A and 124B (shown in two portions in FIG.3) provided on four portions (which may be three portions). Theprojection optical system 104 is held in a central portion of anintermediate support plate of the base member 102. Thevibration-isolating members 124A and 124B are active vibration-isolatingunits that are similar to the vibration-isolating members 123A and 123B.A laser interferometer 111 (reticle interferometer) is provided on anupper surface of the second frame 102B. The laser interferometer 111 anda movable mirror 119 provided on the reticle stage 107 b are used tomeasure the position of the reticle stage 107 b (reticle R) in theindividual X and Y directions. In addition, as needs arises, theindividual rotational angles around the X, Y, and Z axes are measured byusing the laser interferometer 111 and the movable mirror 119. Accordingto the measurement values, a control system (not shown) controls theposition and the movement speed of the reticle stage 107 b. On the otherhand, a supporting frame 112 of the reticle alignment system is disposedon the second frame 102B, and a reticle alignment microscope (not shown)is fitted to an upper portion of the reticle stage 107 b of thesupporting frame 112.

The wafer W is held on a process-piece table 105 a via a wafer holder(not shown), and the process-piece table 105 a is fixedly arranged on anXY stage 105 b. The XY stage 105 b continually moves the process-piecetable 105 a (wafer W) on a wafer base 122 in the Y direction. As needsarises, the XY stage 105 b step-moves the process-piece table 105 a ineach of the X and Y directions. The process-piece table 105 a controlsthe wafer W for a focus position (position in the Z direction) as wellas a slope angle around each of the X and Y axes. The XY stage 105 b isdriven by, for example, a drive section (not shown) using a liner motormethod in such a manner as to satisfy the law of conservation ofmomentum. This inhibits vibrations that can occur when the XY stage 105b is driven. The wafer base 122 is disposed on the base member 102C viavibration-isolating members 125A and 125B (shown in two portions in FIG.3) provided on four portions (which may be three portions). Theprojection optical system 104 is held in a central portion of anintermediate support plate of the base member 102. Thevibration-isolating members 125A and 125B are active vibration-isolatingunits that are similar to the vibration-isolating members 123A and 123B.A wafer stage system WST is configured to include the process-piecetable 105 a and the XY stage 105 b. The wafer stage system WST is housedin box-like third subchamber 106 (wafer room) having ahigh-hermeticality.

A laser interferometer 109 (wafer interferometer) is fixedly arranged onan intermediate of the second frame 102B. A side face of theprocess-piece table 105 a is formed as a movable mirror. The laserinterferometer 109 and the movable mirror of the process-piece table 105a work together to measure the position of the process-piece table 105 a(wafer W) in each of the X and Y directions as well as the rotationalangle thereof around each of X, Y, and Z axes. According to themeasurement values, a stage control system (not shown) controlsoperation of the XY stage 105 b. For example, a multipoint opticalautofocus sensor 110 (AF sensor) employing a grazing incidence method isfixedly arranged on an intermediate support plate of the second frame102B. In addition, the process-piece table 105 a controls the wafer Wfor the focus position of the wafer W as well as slope angle thereofabout each of the X, Y, and Z axes according to information on focuspositions at multiple measurement points on the wafer W measured by theoptical autofocus sensor 110. The process-piece table 105 a performs theabove control by employing an autofocus method and an auto-levelingmethod. Thereby, the surface of the wafer W is focally aligned with animage continually in the projection optical system 104 during exposure.

In addition, a wafer alignment system 114 is fixedly arranged onto thebase member 102. The wafer alignment system 114 employs an off-axismethod and an image-forming method to align the wafer W. Moreover, theconfiguration includes an interface column 117 that houses a reticleloader system RRD and a wafer loader system WRD. The reticle loadersystem RRD performs delivery of the reticle R between itself and thereticle stage system RST. The wafer stage system WST performs deliveryof the wafer W between itself and the wafer stage system WST. In theinterface column 117, gate valves 115 and 116 are provided,respectively, at a transfer opening used for delivery of reticles and ata transfer opening used for delivery of wafers. The gate valves 115 and116 are thus provided to minimize exposure of the respective reticlestage system RST and wafer stage system WST to the outside.

In a scan-exposure operation, upon completion of an exposure of one shotarea of the wafer W, the subsequent shot area is moved to a scancommencement position according to the step movement of the XY stage 105b. Thereafter, synchronous scanning is performed for the reticle stage107 b and the XY stage 105 b on the wafer side by using a projectionmagnification β of the projection optical system 104 as a velocityratio. Specifically, operation in a state in which the image-formingrelationship between the reticle R and the shot area of the wafer W ismaintained is iterated according to the step-and-scan method. Thereby, apattern image is serially transferred onto individual shot areas of thewafer W.

The projection exposure apparatus of the present embodiment includes thefeeding/exhausting mechanism 113 for replacing (purges) gas in spacingsincluding the optical path of the exposure beam with gas (purge gas). Aportion of the illumination optical system, the reticle stage systemRST, and the wafer stage system WST are housed, respectively, in thesubchambers 103, 108, and 106 each having a high hermeticality. Spacingsbetween the individual optical members in the projection optical system104 are arranged as lens rooms having a high hermeticality (the lensrooms also correspond to hermetic rooms). A high-purity purge gas is fedby the feeding/exhausting mechanism 113 into the subchambers 103, 108,and 106. In addition, a high-purity purge gas is fed into the individuallens rooms in the projection optical system 104 (which hereafter will bedescribed in detail).

Filmy covers 101A to 101D each having a high flexibility are provided,respectively, in a boundary portion between the first subchamber 103 andan upper portion of the second subchamber 108, a boundary portionbetween a bottom surface of the base member 121 and an upper surface ofthe second frame 102B, a boundary portion between an upper end portionof the projection optical system 104 and an upper surface of the secondframe 102B, and a boundary portion between a bottom surface of anintermediate support plate of the second frame 102B and an upper surfaceof the third subchamber 106. The covers 101A to 101D are provided insuch a manner as to separate the individual in side spacings from theoutside. In addition, flexible cylindrical filmy covers 118A and 118Bare provided between the second subchamber 108 and the third subchamber106 and the gate valves 115 and 116 in the interface column 117. Thefilmy covers 101A to 101D, 118A, and 118B correspond to flexible filmycovering members of the present invention. These filmy covers can alsobe called soft shield members or bellows each having an extremely lowrigidity. Since the filmy covers 101A to 101D, 118A, and 118Bsubstantially hermetically enclose the boundary portions, the opticalpath of the exposure beam is almost completely hermetic-enclosed. Assuch, almost no gas containing absorptive substances intrudes from theoutside, and the attenuation amount can be reduced subsequently low.

The feeding/exhausting mechanism 113 is configured of a collectingsection for collecting purge gas, a storage section for storinghigh-purity purge gas, and a feeding section for regulating the purgegas in temperature and feeding the gas to the outside. Thefeeding/exhausting mechanism 113 thus configured individually feeds thehigh-purity purge gas into the subchambers 103, 108, and 106 and theprojection optical system 104 via a feed pipeline 126 at a gas pressure(positive pressure) that is slightly higher than the atmosphericpressure. In addition, via an exhausting pipeline 127 having a valve V,the feeding/exhausting mechanism 113 collects impurity- containing purgegas that flowed inside of each of the subchambers 103, 108, and 106 andthe projection optical system 104. Furthermore, the feeding/exhaustingmechanism 113 separates purge gas from the collected gas; and then, itcompresses the separated purge gas at a high pressure; or alternatively,it liquefies the purge gas and temporarily stores it. An exampleconfiguration is described hereinbelow. For example, impurity sensorsfor measuring the concentration of oxygen as absorptive substance areprovided inside of the subchambers 103, 108, and 106 and the projectionoptical system 104. Suppose the concentration of the absorptivesubstance that was detected by each of the impurity sensors has exceededa predetermined tolerance value. In this case, collection of gas via theexhausting pipeline 127 and compensatory feed of the high-purity purgeare implemented according to a gasflow control method that controls gashaving substantially constant pressure (slightly higher than theatmospheric pressure) to flow. As such, even in the configuration usingthe highly flexible filmy covers filmy covers 101A to 101D, 118A, and118B, no excessively great force exerts on the filmy covers filmy covers101A to 101D, 118A, and 118B.

In the above, the tolerance value of the concentration may be arrangedto be variable depending on the type of absorptive substance as in anarrangement in which a tolerance value for the concentration for organicsubstance is set lower than a tolerance value for the concentration ofcarbon dioxide. In addition, an arrangement may be made such thatportions where the reticle loader system RRD and the wafer loader systemWRD are housed in the interface column 117 are hermetically enclosed,and the purge gas is fed into the spacings. In this case, thearrangement may be made such that the purge gas used to process thecollected gas as described above from the subchambers 103, 108, and 106and the projection optical system 104 is fed into the interface column117; and an unused high-purity purge gas stored in the purge-gas storagesection is fed into the subchambers 103, 108, and 106 and the projectionoptical system 104.

The tolerance value for the concentration of impurities in theabove-described individual subchambers and the projection optical systemis not limited to the above- described tolerance value (10 to 100 ppm).The value may be different depending on the place.

In addition, when the purge gas is fed, the feeding/exhausting mechanism113 regulates, for example, the temperature, humidity, and the pressureof the purge gas to be fed. Concurrently, the feeding/exhaustingmechanism 113 removes the above-described absorptive substances and thelike from the purge gas by using a dust-removing filter such as a HEPAfilter (high efficiency particulate air-filter) and a chemical filterfor removing the above-described absorptive substances containingorganic substances and the like. Substances to be removed includesubstances that adhere to optical elements used in the projectionexposure apparatus to thereby cause the elements to be cloudy. Theimpurities to be removed also include substances that flow in theexposure-beam optical path and causes variations in, for example, thetransmittance (illuminance) or the illuminance distribution of theillumination optical system and the projection optical system. Inaddition, the impurities to be removed include substances that adhereonto a surface of the wafer W (resist) to thereby cause apostdevelopment pattern image to vary. A usable filter is anactive-carbon filter (for example, “GIGASORB” (brand name) produced byNitta Corp.), a zeolite filter, or a filter formed by combining thefilters. The filters remove silicon organic substances, such assiloxanes (substance containing a chain of Si—O as a base) or silazanes(substance containing a chain of Si—N as a base).

As described above, by replacing the ambient atmosphere of the opticalpath of the exposure beam, the transmittance for the exposure beam ishighly maintained. Accordingly, the illuminance of the exposure beam ledto be incident on each shot area is increased. Consequently, thisreduces the exposure time for each shot area, thereby enabling thethroughput to be improved.

In addition, in the present embodiment, optical paths of measurementbeams of optical measuring units, such as the laser interferometers 109and 111 and the optical autofocus sensor 110, are set in the ambientatmosphere of the purge gas. This arrangement inhibits measurementerrors from occurring because of fluctuations in gas along the opticalpaths of the optical measuring units.

Next, referring to FIGS. 4 and 5, a detailed description will be maderegarding the filmy covers 101A to 101D, 118A, and 118B. Hereinbelow, aconfiguration of the representative filmy cover 101A will be described.

FIG. 4 shows a state in which the filmy cover 101A is set. Referring toFIG. 4, flanges 130 and 131 formed of, for example, metal such asaluminum, or ceramics, are provided at two ends of the filmy cover 101A.The filmy cover 101A is set in such a manner as to cover a portionbetween the lower end of the first subchamber 103 and the upper end ofthe second subchamber 108 via the flanges 130 and 131. The flanges 130and 131 are fixed onto fit planes. In this case, to increase thehermeticality, for example, O-rings formed of a material having alow-degasification property (such as a fluorine-based resin) may beplaced between the flanges 130 and 131 and the fit planes.

FIG. 5 is a thickness-wise-enlarged transverse cross sectional viewshowing the filmy cover 101A shown in FIG. 3. As shown in FIG. 5, thefilmy cover 101A of the present embodiment is formed as follows. Aprotection film 101 d is coated on an outer surface of a film material101 c via an adhesive. The film material 101 c is made of an ethylene-vinyl-alcohol resin (EVOH resin). The protection film 101 d has a highexpandability and is formed of polyethylene (—(CH₂CH₂)_(n)—). Inaddition, a stabilization film 101 b made of aluminum (Al) is coated onan inner surface in a manner of, for example, deposition. Theethylene-vinyl-alcohol resin (EVOH resin), for example, “EVAL” (brandname) produced by Kuraray Co., Ltd. may be used. The stabilization film101 b is preferably formed of a material that does not causedegasification or that has a very low degasification property.

The filmy cover 101A is formed such that lamination processing(multilayer processing) is performed for the protection film 101 d(third material) and the film material 101 c (first material), and thestabilization film 101 b (second material) is coated in the innersurface thereof. The protection film 101 d is inherently excellent inexpandability, the film material 101 c is excellent in gas-barrierproperty, and the stabilization film 101 b has a significantly lowdegasification property. The overall thickness of the filmy cover 101Ais about 0.1 mm. To cylinderically form the filmy cover 101A, an endportion A is formed such that two end portions of the protection film101 d, which has a high weldablility, are connected to oppose eachother, and are welded together; and the welded portion is completelyhermetically enclosed.

In this case, while the protection film 101 d has a high expandability,it has disadvantages in that the gas-barrier property is relatively low,degasification can easily occur, and metal and the like cannot easily beattached to an inner surface thereof. Taking the above into account, thepresent embodiment is arranged as follows. The film material 101 c isformed that has a high gas-barrier property to enable the prevention ofintrusion of outside air as well as leakage of the purge gas. Inaddition, the film material 101 c onto which metal and the like caneasily be attached is formed, and the stabilization film 101 b is formedin the inside thereof. Furthermore, the stabilization film 101 bprevents the adhesive used to form the filmy cover 101A anddegasification-produced gas occurring as a result of heat-sealing andthe like to intrude into the inside of the filmy cover 101A, that is,the optical path of the exposure beam. Still furthermore, a shieldingproperty against gas is even more improved since the stabilization film101 b is applied onto the inner surface.

As described above, the filmy cover 101A of the present embodiment isformed of the materials, such as the film material 101 c having a highflexibility, that is, a very low rigidity and a high gas-barrierproperty. As such, in comparison to the configuration using only themetal below mechanisms, an equivalent gas-barrier property is obtained,and in addition, almost no vibrations are propagated between the firstsubchamber 103 and the second subchamber 108 (reticle room), which areshown in FIG. 3. Moreover, the other filmy covers 101B to 101Dm 118A,and 118B are formed in the same manner as that for the above-describedfilmy cover 101A. As such, vibrations are not easily propagated betweenthe adjacent hermetic rooms.

Accordingly, almost no influences of vibrations and unbalanced loads in,for example, the reticle stage system RST and the wafer stage systemWST, which are shown in FIG. 3, are propagated to, for example, theprojection optical system 104 and the second frame 102B. That is, theconfiguration enables the reduction in the image-forming property of theprojection optical system 104 according to the defective vibrations andunbalanced loads to be minimized. Consequently, the configurationenables high-precision exposures to be implemented. In addition, theconfiguration enables the inhibition of occurrence of measurement errorsthat can occur with the laser interferometers 109 and 111, thesupporting frame 112 for the reticle alignment system, the waferalignment system 114, and the optical autofocus sensor 110 that arefitted to the second frame 102B.

In addition, in the present embodiment, the filmy covers 118A and 118Bare disposed, respectively, between the reticle stage system RST (secondsubchamber 108) and the interface column 117 and between the wafer stagesystem WST (third subchamber 106) and the interface column 117. Thisconfiguration enables the prevention of vibrations occurring in thereticle loader system RRD and the wafer loader system WRD in theinterface column 117 to propagate to the main body of the projectionexposure apparatus. Furthermore, the gate valves 115 and 116 areprovided on the side of the interface column 117. The configurationenables influences of vibrations occurring by on/off operations of thegate valves 115 and 116 to be inhibited.

The material used for the filmy covers 101A to 101D, 118A, and 118B isnot limited to the ethylene-vinyl-alcohol resin. Any material may beused as long as it has a high shielding property against gas and a highflexibility. Usable materials therefor are, for example, polyamide,polyimide, and polyester. As a material having a highest gas-barrierproperty, the ethylene-vinyl-alcohol resin is preferable. As a materialthat is inexpensive and hence economical, a polyester material ispreferable. In view of cost performance, polyamide or polyimide ispreferably used.

The material to be coated as the protection film 101 d onto the innersurface of the filmy covers 101A to 101D, 118A, and 118B is not limitedto the aluminum used in the present embodiment. Any material, includingother metals and inorganic materials such as ceramics, may be used aslong as it has a high reactivity to an exposure beam such as vacuumultraviolet light and a low degasification property. Moreover, for theprotection film 101 d, instead of polyethylene, polypropylene may beused.

In the configuration used with a small differential between pressuresin, for example, the hermetic rooms (such as the subchamber 103) and theoutside, each of the filmy covers 101A to 101D, 118A, and 118B may beformed only of the film material 101 c and the stabilization film 101 b.Moreover, in the configuration in which, for example, the amount ofdegasification is small, each of the filmy covers 101A to 101D, 118A,and 118B may be formed only of the film material 101 c.

The number of filmy covers as the filmy covers 101A to 101D, 118A, and118B and the provision portions thereof are not limited to those in theconfiguration of the present embodiment. The filmy covers may beoptionally provided to hermetically enclose the optical path of theexposure beam or to hermetically enclose portions communicated with theoptical path (such as the provision portion of the reticle loader systemRRD). For example, in a configuration in which each stage system isdriven using a counterbalance to satisfy the law of conservation ofmomentum, the filmy covers may be provided in a spacing between thecounterbalance and a movable stage of the stage system.

Hereinbelow, another example of the filmy cover (covering members) willbe described with reference to FIGS. 6A and 6B.

FIG. 6A shows a filmy cover 141 of the present example. Similar to theabove-described filmy covers 101A to 101D, 118A, and 118B, the filmycover 141 of the present embodiment is formed by laminating materialssuch as a film material having a high gas-barrier property and aprotection film having a high expandability. As described above, each ofthe filmy covers 101A to 101D, 118A, and 118B is cylindrically formed bywelding end portions of the protection film 101 d that are held tooppose each other. However, the filmy cover 141 of the present exampleis formed such that joint portions of a member cylindrically bend-formedare connected using a protection film 141 a attached such as to coverthe joint portions.

In more specific, as shown in FIG. 6B, the filmy cover 141 of thepresent example is formed as follows. A polyethylene protection film 141d having a high expandability is applied on an outer surface of a filmmaterial 141 c made of an ethylene-vinyl-alcohol resin via an adhesive141 e. Then, a protection film 141 a having a high weldability is weldedor adhered with an adhesive in such a manner as to cover the outside ofthe outer joint portions. In addition, similarly to each of theabove-described filmy covers 101A to 101D, 118A, and 118B, astabilization film 141 b made of aluminum is applied onto an innersurface of the film material 141 c in a manner of, for example,deposition. An overall thickness d1 of the filmy cover 141 is about 0.1mm. A thickness d2 of the connection-dedicated protection film 141 aused to cylindrically form the filmy cover 141 is about 0.03 mm.

In the filmy cover 141 thus formed by using the material such as theprotection film 141 a having a high weldability to connect two endportions, uneven (or stepped) portions tending to cause impurities tostay on the inner surface of the filmy cover 141 are reduced. Inaddition, in the above-described construction, the amount of leakage ofthe purge gas is reduced. As such, the construction is advantageous inthat the inside of the filmy cover 141 can be purged even moreefficiently.

To provide a simplest construction of the connected portion of the filmycover, the construction may be made such that an outer surface of oneend portion is simply overlapped with an inner surface of the other endportion by a predetermined width, and the overlapped portions are fixedby adhesion or welding.

The above-described filmy covers 101A to 101D, 118A, 118B, and 141 areformed of planar materials. However, filmy covers as covering membersmay be individually formed as a bellows. With the covering membersformed as a bellows, a fitting procedure of the cover members can besimplified, or the durability against inside and outside pressures canbe improved depending on the case.

The covering members as the filmy covers 101A to 101D, 118A, 118B, and141 need not be provided in all the above-described connected portions,and may be provided in at least one connected portion. Moreover, whenthe illumination optical system or the projection optical system isseparated and stored into a plurality of hermetic rooms. This applies aswell to a case in which the reticle loader system RRD or the waferloader system WRD is separated and stored into a plurality of hermeticrooms. In addition, filmy covers may be provided for connected portionsbetween a lens housing provided for housing portions of the opticalsystems (for example, the wafer alignment system 114, the opticalautofocus sensor 110, and the laser interferometers 109 and 111), whichare provided around the second subchamber 108 or the third subchamber106, and the corresponding subchambers. Moreover, filmy covers may beprovided in connected portions between the pipelines provided forfeeding and exhausting purge gas and the above-described individualsubchambers and the projection optical system.

Also in the projection exposure apparatus of the first embodiment (shownin FIG. 1), instead of the bellows 25, 36, and 43, the filmy covers ofthe second may be employed. Alternatively, the stabilization film 101 bof the second embodiment may be provided in an inner surface of each ofthe bellows 25, 36, and 43. Moreover, while the bellows of the firstembodiment or the filmy covers of the second embodiment are each formedto have an inner surface formed of a material having a lowdegasification property, a case may occur in which degasification-causedgas occurs. In such a case, a suction pipe is preferably connected to aportion of the bellows or the filmy cover to collect thedegasification-caused gas.

Each of the above-described embodiments represents the example of thepresent invention applied to the projection exposure apparatus employingthe step-and-scan method. However, it should be apparent that thepresent invention can be applied to a projection exposure apparatus of afull-field-exposure type as well as to a mirror-projection exposureapparatus and proximity exposure apparatus that does not use aprojection optical system.

In a configuration using a projection optical system, an optical systemtherefor may be any one of a dioptric system, a reflection system, and acatadioptric system. Furthermore, the optical system may be of any oneof an image-reduction system, an image-equalization system, and animage-magnification system.

While the present invention can be applied to exposure apparatuses usedfor manufacturing microdevices such as semiconductor devices, thin-filmmagnetic heads, and image pickup devices (charge-coupled devices(CCDS)), the present invention can also be applied to an exposureapparatus for transferring circuit patterns onto, for example, glasssubstrates or silicon wagers, to manufacture reticles or masks.Generally, in an exposure apparatus using, for example, DUV (deepultraviolet) light, or VUV (vacuum ultraviolet) light, a transmissionreticle is used. In addition, the apparatus uses for example, quartsglass, fluorine-doped quarts glass, fluorite, magnesium fluoride, orquarts, as a reticle substrate. In an exposure apparatus using EUV(extreme ultraviolet) light, a reflection mask is used as an exposureenergy beam. In a proximity X-ray exposure apparatus or an electron-beamexposure apparatus, a transmission mask (such as a stencil mask ormembrane mask) is used; and a silicon wafer or the like is used as amask substrate.

In addition, the present invention can be applied to a case where, forexample, an infrared-region or visible-region mono-wavelength lasergenerated from a DFB semiconductor laser or a fiber laser is amplifiedby a fiber amplifier doped with, for example, erbium (Er) (or botherbium and ytterbium (Yb)), and a harmonics converted in wavelength intoultraviolet light by using nonlinear optical crystal.

In more specific, when a generation wavelength of the mono-wavelengthlaser is set within a range of from 1.51 to 1.59 μm, there is outputeither an eight-fold harmonics in which the generated wavelength iswithin a range of from 189 to 199 nm or a ten-fold harmonics in whichthe generated wavelength is within a range of from 151 to 159 nm. Inparticular, when the generation wavelength is set within a range of from1.544 to 1.553 μm, there is output an eight-fold harmonics in a range offrom 193 to 194 nm. That is, ultraviolet light having substantially thesame wavelength as that of an ArF excimer laser can be obtained. Inaddition, when the generation wavelength is set within a range of from1.57 to 1.58 μm, there is output a ten-fold harmonics in a range of from157 to 158 nm. That is, ultraviolet light having substantially the samewavelength as that of an F₂ laser can be obtained.

Either one of the exposure apparatuses according to the above-describedtwo embodiments can be fabricated in the following manner. Theillumination optical system and the projection optical system, which areconfigured to include a plurality of optical elements, are built intothe main unit of the exposure apparatus, and optical adjustment isperformed. Then, for example, the reticle stage and wafer stageconfigured of a large number of mechanical components are assembled intothe main unit of the exposure apparatus; and wirings, pipelines, and thelike are connected therein. The individual subchambers, the projectionoptical system, and the like are individually connected to, for example,the gas-circulating unit. Then, a total adjustment (including electricaladjustment and operational verification) is performed. Preferably, anexposure apparatus as described above is fabricated in a clean roomcontrolled in temperature, cleanliness, and other environmental factors.

A semiconductor device is manufactured according to, for example, thefollowing procedure. The procedure include a step of designing functionsand performance of the device; a step of manufacturing a reticleaccording to the design step; a step of manufacturing a wafer from asilicon material; a step of performing an exposure operation for areticle pattern onto the wafer; a device-assembling step (including adicing step, a bonding step, and a packaging step); and testing step.

The present invention is not limited to the above- mentionedembodiments, and the invention may be embodied in various forms withoutdeparting from the gist of the present invention. Furthermore, theentire disclosure of Japanese Patent Application 11-149598 filed on May28, 1999 and Japanese Patent Application 2000-51106 filed on Feb. 28,2000 including description, claims, drawings and abstract areincorporated herein by reference in their entirety.

INDUSTRIAL APPLICABILITY

According to the first exposure method of the present invention, aprojection system and stage systems are supported not to easilypropagate vibrations to each other. As such, vibrations in movablesections of the stage systems are not easily propagated to, for example,the projection system. Furthermore, the positions of the movablesections can be measured. Consequently, the exposure method isadvantageous in that the control precision of the movable sections canbe improved.

According to the first exposure apparatus, individually stage systemsand a projection system connected independently of each other viavibration-isolating members. As such, vibrations are not easilypropagated between the individual stage systems and the projectionsystem. Consequently, the first exposure method of the present inventioncan be applied to the apparatus.

In the above, the apparatus is configured such that the projectionsystem is constructed hermetic, chambers individually enclosing aportion of an illumination system and each of the stage systems, andflexible connection members are provided for hermetically enclosingindividual portions between the individual chambers and the projectionsystem. In this configuration, when a high-transmittance gas is fed intoat least a portion of an optical path of an exposure beam, the intrusionamount of an outside gas is reduced. Furthermore, the illumination ofthe exposure can be highly maintained. Consequently, the throughput ofan exposure step is improved.

According to the second exposure method or one of the second and thethird exposure apparatuses, the luminous quantity of an exposure beamused is highly maintained. In addition, even when vibrations occur in ahermetic room, the apparatus exhibits an advantage in that thevibrations are not propagated to other hermetic rooms. For example, evenwhen vibrations have occurred by moving an object of the above, theimage-forming property of the projection optical system, the measurementprecision of a laser interferometer, and the like are not degraded.Consequently, a high-throughput and high-precision exposure can beimplemented.

Furthermore, according to the device-manufacturing method of the presentinvention, by using the exposure method or the exposure apparatus of thepresent invention, a high-precision exposure can be implemented.Moreover, a high-function-level device can be manufactured.

1. An exposure apparatus which transfers a pattern of a mask onto asubstrate, comprising: a covering member which is disposed in saidexposure apparatus and which substantially isolates a predeterminedspacing from outside gas, wherein said covering member includes a firstthin film made of a first material which blocks penetration of theoutside gas with respect to the predetermined spacing, a second thinfilm made of a second material of at least one of a metal and aninorganic substance, and a third thin film made of a third materialhaving an elasticity, the third thin film being formed on an outersurface of said covering member.
 2. An exposure apparatus as recited inclaim 1, wherein said second thin film is formed on an inner surface ofsaid first thin film.
 3. An exposure apparatus as recited in claim 2,wherein the third thin film is formed on an outer surface of said firstthin film.
 4. An exposure apparatus as recited in claim 3, wherein saidthird thin film is formed by lamination processing with respect to saidfirst thin film.
 5. An exposure apparatus as recited in claim 4, whereinsaid covering member is formed in a cylindrical shape, and saidcylindrical shape is formed by securing said third material to itself atboth end portions of said covering member in a state in which saidcovering material of a sheet shape is rolled into the cylindrical shape.6. An exposure apparatus as recited in claim 4, wherein said thirdmaterial at both end portions of said covering member is secured toitself by welding.
 7. An exposure apparatus as recited in claim 2,wherein said second thin film is formed by evaporating and depositingsaid second material onto said first thin film.
 8. An exposure apparatusas recited in claim 3, wherein the first material is at least one ofethylene-vinyl-alcohol, polyamide, polyimide and polyester, the secondmaterial is at least one of aluminum and ceramics, and the thirdmaterial is polyethylene.
 9. An exposure apparatus as recited in claim3, wherein said first thin film and said second thin film are secured toeach other by an adhesive.
 10. An exposure apparatus as recited in claim1, wherein said predetermined spacing is a part spacing of an opticalpath spacing for an exposure beam which transfers said pattern of saidmask onto said substrate.
 11. An exposure apparatus as recited in claim10, further comprising: an illumination system which illuminates saidmask; a first chamber which accommodates said illumination system; and asecond chamber which accommodates a first stage system which positionssaid mask, wherein said predetermined spacing is a space between saidfirst chamber and said second chamber.
 12. An exposure apparatus asrecited in claim 10, further comprising: a projection system whichtransfers said pattern of said mask onto said substrate; and a thirdchamber which accommodates said second chamber which positions saidsubstrate, wherein said predetermined spacing is a spacing between saidprojection system and said third chamber.
 13. An exposure apparatus asrecited in claim 1, further comprising: two hermetic rooms which aredisposed in said exposure apparatus and which are adjacent to eachother, wherein said covering member is disposed between said twohermetic rooms and isolates a spacing between said two hermetic roomsfrom the outside gas as said predetermined spacing.
 14. An exposureapparatus as recited in claim 13, wherein one of said two hermetic roomsaccommodates said first stage system, and the other of said two hermeticrooms accommodates a loader system which transfers said mask to saidfirst stage system.
 15. An exposure apparatus as recited in claim 13,wherein one of said two hermetic rooms accommodates said second stagesystem which positions said substrate, and the other of said twohermetic rooms accommodates a loader system which transfers saidsubstrate to said second stage system.
 16. An exposure apparatus asrecited in claim 1, wherein said covering member is formed in a bellowshape.
 17. An exposure method which transfers a pattern of a mask onto asubstrate, comprising: isolating a part spacing of an optical pathspacing for an exposure beam which transfers said pattern of said maskonto said substrate from outside gas by using a covering member whichincludes a first thin film made of a first material which blockspenetration of the outside gas with respect to said part spacing, asecond thin film made of a second material of at least one of a metaland an inorganic substance, and a third thin film made of a thirdmaterial having an elasticity, the third thin film being formed on anouter surface of said covering member, supplying gas through which saidexposure beam passes to said part spacing which is isolated from theoutside gas by said covering member, and transferring said pattern ofsaid mask onto said substrate in a state in which said gas is suppliedto said part spacing.
 18. An exposure method as recited in claim 17,wherein said second thin film is formed on an inner surface of saidfirst thin film.
 19. An exposure method as recited in claim 18, whereinthe third thin film is formed on an outer surface of said first thinfilm.
 20. An exposure method as recited in claim 19, wherein said thirdthin film is formed by lamination processing with respect to said firstthin film.
 21. An exposure method as recited in clam 20, wherein thefirst material is at least one of ethylene-vinyl-alcohol, polyamide,polyimide and polyester, the second material is at least one of aluminumand ceramics, and the third material is polyethylene.
 22. An exposuremethod as recited in claim 18, wherein said second thin film is formedby evaporating and depositing said second material onto said first thinfilm.
 23. An exposure method as recited in claim 17, wherein said partspacing is a spacing between an illumination system which illuminatessaid mask and a projection optical system which transfers said patternof said mask onto said substrate.
 24. A device manufacturing method,comprising transferring a mask pattern onto a substrate by using theexposure method as recited in claim
 17. 25. An exposure apparatus whichtransfers a pattern of a mask onto a substrate, comprising: a coveringmember which is disposed in said exposure apparatus and whichsubstantially isolates a predetermined space from outside gas, whereinsaid covering member includes a first thin film made of a first materialwhich has a expandability and which generates degasification-caused gas,said first thin film forming an outer surface of said covering member, asecond thin film which is disposed on a side of said predetermined spacewith respect to said first thin film and which is made of a secondmaterial, said second thin film blocking the degasification-caused gasfrom penetrating into said predetermined space, and a third thin filmmade of a third material and disposed between said first thin film andsaid second thin film, said first thin film being joined on said secondthin film with said third thin film, and said third thin film blockingthe outside gas from penetrating into said predetermined space.
 26. Anexposure apparatus as recited in claim 25, wherein the first material ispolyethylene, the second material is at least one of aluminum andceramics, and the third material is at least one ofethylene-vinyl-alcohol, polyamide, polyimide and polyester.
 27. Anexposure apparatus as recited in claim 25, wherein said first thin filmand said third thin film are secured to each other by an adhesive.